About every 15 years the two planets will form mutual aspects by solar arc within a year of each other.

大约每过15年，这两颗行星会在年度内太阳弧推运中相互间形成相位。

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Shown above is a photo of the sun peeking from behind a building, with a 22-degree solar halo arc shining around it.

上面显示的那张照片，是在一座建筑物后面窥视太阳时所拍摄的，带有一个22度的日晕弧在围绕着太阳闪耀。

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This arc is 65 times larger than the diameter of our solar system.

这个弧形比太阳系直径的65倍还要大。

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The kilometre-wide separation of the component satellites of Terrestrial Planet Finder should allow it to see planets in distant solar systems a problem akin to looking for moths flying around a football-stadium arc light that is several hundred kilometres away.

ECONOMIST: Birds of a feather